A conventional swimming pool installation usually employs a pump and filter located adjacent to the pool for circulating and filtering the pool water. Typically, a skimmer assembly is installed in the wall of the pool in order to skim off the upper surface of the pool water before the water is circulated to the pump and filter. More particularly, the skimmer assembly includes a strainer basket adapted to remove coarse debris which may be floating on top of the pool water. One drawback of such a skimmer assembly is its inability to remove fine debris from the pool water. This drawback is not terribly critical when the skimmer assembly is operating in a skimming mode because, in such a mode, only the top surface of the water is being treated. However, for skimmer assemblies adapted to function in a vacuuming mode as well as in a skimming mode (see, for instance, U.S. Pat. Nos. 2,844,255; 2,900,079; 2,979,206; 3,864,262; 4,126,925 and 4,348,281), the inability to filter out fine debris becomes a more significant problem due to the fact that the water which is vacuumed from the bottom of the pool contains fine debris as well as coarse debris.